Torsional-ptvot balance



(NoModelJ P. A. BORDER 85 A. SPRINGER.

TORSIONAL PIVOT BALANCE. No. 310,542. I Patented Jan. 6, 1885.

TORSlGNAL-PlVGT El -i;

SPECIFICATION forming part of Letters Patent 230. 31 3,5 12, date;

Application filed March til, 'lSSl.

1'0 (tZZ whom it may concern:

Be itknown that we, FREDERICK A. ltonnnn and ALFRED SPRINGER, citizens of the United States, residing at Cincinnati, Ohio, have invented new and useful Improvements in Torsional-Pivot Balances, of which the following is a specification.

Our invention relates to that class of balances in which, as a substitute for knifeedges or similar fixed fulcrum-supports, an elastic body is employed as a fulcrum acting upon the principle of molecular displacement-as, for example, a stretched metallic wire acting torsionally.

In ordinary fulcrum-balances it is essential that the center of gravity be below the center of oscillation of the beam, in order that the beam,when deflected from its normal position of rest, shall return thereto. Itis also an obvious condition that increase of weight, as in loading the scale in use, increases the friction of the fulcrum-supports, and, further, that a like result attends the multiplication of levers, which renders such construction of ordinary fulcrum balances impracticable for delicate uses. In the class of scales to which our invention is applied, however, the beam is returned to its normal position by the mo lecular elasticity of the fulcrum support. Consequently the center of gravity may be above the center of oscillation, and the element of friction being eliminated, the only difficulty to be overcome in multiplying the leverage, while retaining sensit-iveness, is the increased resistance to deflection of the beams from the position of rest; but this diiliculty is within control,while friction is not, and it is the obj eet of ourinventionto avail ourselves of these radical differences between the two classes of balances and produce balances of extraordinary sensitiveness and capacity. In such scales it has been found that a weight or poise arranged upon avertical standard oscillatin g with the beam and opposing an increasing weight by leverage to the increasing resistance of the elastic fulcrum and terminal pivots counterbalan ces such resistance and adds essentially to the sensitiveness of the balance. This, however, we do not assert as our joint invention, the same being covered by the application of Dr. Itoeder, now 011 file, filed July 10, 1881-, Serial No. 137,293; but we find that where a January 6, 13855.

(No model.)

connected series of lovers isemployedas, for example, in platform-sealesthe weight used as a poise to elevate the center-of gravity may be applied to each of the levers separately,or to any one of the series, preferably to the last, and upon this principle a scale may be constructed having extreme delicacy combined with a magnified range'of notation.

Ourinvention then consists in a balance mbodying the above-stated irinciple.

In the accompanying drawings, illustrating our invention, Figure l is an elevation of a simple torsional-pivot scale to which our invention is applied. Fig. 3 is an elevation of an ordinary torsionalpivot groeers scale or platfornrbalance to which our invention is applied by mounting the poise upon a pivoted standard orpointerconnected with the last lever of the series; Fig. l, a modification of the foregoing, showing additional levers with the poise mounted directly upon the last of the series; and Fig. an elevation of a multiplied lever-balance for delicate uses, showing the poises appliedto each of the beams. Fig. 6 is an end view, and Fig. 7 a plan,ofsomuch of a balance as is necessary to show atorsionpivot. Fig. 8 is aperspective viewol' so much of the device as is necessary to illustrate the central portion of a scale-beam, a torsional pivot, and pivot-supports.

teferring now to the drawings, A designates an ordinary scalebeam mounted upon a central fulcrum consisting of an elastic bodysuch as a stretched metallic wire, pwhich by its torsional resistance opposes the oscillation of the beam from its normal position of rest. Now, it is obvious that the resistance in such case increases uniformly in proportion to the amount of deflection of the beam from its point of rest, and that with the increased strength of metal required for pivots of scales for heavy weights the torsional resistance is also increased to a degree impairing the sensitiveness of the scale. To overcome this dii'liculty and render the resistance practically uniform at any deflected position of the scale beam, we attach to the beam a central vcrti cal standard, B, and provide the same with a weight, 0, preferably adjustable; and in order that the center of gravity may not be lowered below the center of rotation and the counterbalancing eli'cct lost by loading the scale-pans Lil in the ordinary use of the scale, we elevaie the points of load-suspension to the line of the center of gravity of the balance. Supposing the line of the center of gravity to be as represented by too dotted line, Fig. l, the ends of the beam or the points of suspension of the scale-pans a e arranged in that line. This may be done either by bending; the beam upward, L s shown in Fig. l, or oy turning up the ends merely.

The same principles rpply "o lIlilll/iplled hean1-scalcs,wilh the important additiona principle already rci'crreo to, in embodiment of which is shown in l igs. 3, and 5.

In the ordinary platform-scale (shown in lllg. S) I? designates the Plli'illl'lil, and L It primary and secondary suppo1l n5;levers the connections being; torsional pivots p, 01' stretched metallic wires, requiring no s ccia description. in the case shown as a1 {er of convenience of construction, the lover if is a bell-cranl having a depending arm, 5, connected at its lower end by a ink on torsional pivots with a p otcd stan lard, S, serving I the double purpose of apoii er and a standard for the support of the an just-able poise c.

It is obvious that the ei'i'zct oi would be precisely the same I l ard carrying the weight arrange ve above the center of rotation of a1 d i 2 rtachcd to the bean if. This construction 1 shown in Fig. 4, in which the sandard S *nrrying the poise c, is )l:'iccd above the center rotation of a lever L", c nnccted with 1y an i three intermediate lever, 11', the:

n JV 'aug'cd parallel to each oiher i Zillii with. sliding; weights in, and proportioned to indicate certain definite relations of weights upon the platform.

In Fig. 5 the levers L L'' L" are arranged in simple consecutive order connected by links (1 on torsional pivots p, and each lever provided with a poise, (1; but any two maybe dispensed with and only one, preferably the last, retained.

By the use of the connterbalancing-poiscs the scale shown in Fig. 5 possesses great delicacy and SOHSitiVQHQSS, yet gives awid: 2 re of notation at the lever L.

We claim as our invention and desire to cure by Letters Patent 1. A beam balance having its center of 'avity above the center of rotation, and havil's loadsupporls suspended from points a line with the center of gravity of the balincc, in combination with a supporting-pivot which acts torsionally by molecular displace nient :ribstanlially as described.

in a balance, a connected system of leers, each hung on an elastic torsional pivot, and a counterpoise ionnectcd to one only of the levers, vertically above its pivot so as to conirol the movement of tl e series, substantially as described.

In testimony whereof we have hereunto sct our l ands in the presence of two subscribing sscs: ii. iii. llosm, (j. 113m Print. 

